Program selecting system



March .31, 1936. T, C, R|EBE ET AL 2,035,617

PROGRAM SELECTING SYSTEM Filed sept. 9, 1929 Fi i Fig. E 3/ 22 25 34* 636' Fi 5 2 304/42 f 26 22 27 44 Patented Mar. 31, 1936 GFFIE PROGRAM sELEo'rING SYSTEM Application September 9, 1929, Serial No. 391,326 s claims. (01.179-1) springs which connect the subscribers line with a receiver which is tuned to receive a particular program.

Another feature of the invention lies in the provision of a resistance for each set of springs so connected that it is substituted for the subscribers loud speaker when the switch is stepped to another position. Thus the volume of reception of the other subscribers listening to a program is not affected when one subscriber operates his switch to select another program.

A further feature of the invention lies in the provision of an improved pawl which is designed to prevent overthrow of the shaft and cams when the switch is operated.

Other features of the invention will become apparent from the following specification when read in connection with the accompanying drawing in which:

Fig. 1 represents a plan View of the selector switch showing the armature in normal or unoperated position;

Fig. 2 isa side view of the switch showing one of the spring combinations provided for each cam;

Fig. 3 is a section taken along the line 3 3 of Fig. 1 and shows the improved pawl with the armature in operated position; and

Fig. 4 is a schematic circuit diagram showing the improved switch used as a selector in a radio program service system.

Referring to the drawing, the switch consists essentially of a coil 2 having a magnetic core I which is secured to the U-shaped magnetic yoke I by means of a nut threaded on the bolt 50. The upper ends of the yoke I are held rigid by the non-magnetic rods I3, 26, and 2l. The movable armature, indicated generally at I, is U-shaped and is pivoted on the rod i5 extending between the two sides of the yoke I. The armature is equipped with a screw 8 for adjusting the residual of the switch. A screw 9 is threaded through the armature and locked by means of a nut. The portion of this screw projecting through the armature is tted with a small insulating bushing and operates the springs I I and I2 when the armature is in operated position. These springs are fastened to the upper spool head by means of a screw. The spring II has a projecting portion I 4 which is bent at right angles to the spring and serves as a terminal. Spring I2 is equipped with a contact point at its free end which makes contact with a second contact point and terminal I3, also secured to the spool head, when the armature is in operated position.

Two non-magnetic plates 5I and 52 are at` tached to the inner sides ofthe two arms of yoke I. A portion of plate 5I is formed into a hook 20 at right angles to the plate to which is attached the armature restoring spring I1. To one arm of the U-shaped armature-is pivoted the nonmagnetic pawl 23.

The yoke, coil, armature, insulating plates, restoring spring, and armature contact springs briey described above are similar to the corresponding parts of the improved counting meter illustrated, described and claimed in the copending application of Obergfell and Riebe, Serial No. 285,114, led June 18, 1928, and the detailed construction and operation of this mechanism will not be explained here.

The shaft 2| passes through holes in the upper ends of the yoke I and the insulating plates 5I and 52. The holes through the yoke are somewhat larger than the shaft while the holes through the plates are only slightly larger than the shaft whereby the latter serve as bushings for the shaft. Endwise motion of the shaft is prevented by the collar 53 Vand the collar and ratchet wheel 22 which are locked to the shaft by means of screws just inside the insulating plates.

The fiber cam wheels are mounted on those portions of the shaft which extend through the yoke I. In the particular switch illustrated, five cams are shown but it will be appreciatedV that the switch is not limited to ve cams but may be equipped with a larger or smaller number depending upon the service for which it is to be used. Two cam wheels 3U and 3l are mounted on a collar 29 which is placed on one end of the shaft and locked in position by means of the set screw 32. A similar collar 33 mounting three cam Wheels, 34, 35, and 36, is fastened to the other end of the shaft by means of set screw 31.

A right-angled bracket 5 is fastened to the side of the yoke I by means of screws 6 and on this bracket are mounted two 'sets of springs in such a position to be operated by the projections on the faces of the cam Wheels. A similar. bracket 3 ture is operated, the pawl is pulled downward .Y

turning the shaft and associated cam wheels through one-tenth of a revolution. This operates the next succeeding set of. springs by means of one of the projections on the succeeding cam wheel. When the armature is at the bottom of its stroke or fully operated, the hook-like projection 24 of the pawl comes into' contact with the back face of one of the ratchet teeth thereby preventing any further movement or overthrow of the switch. The detent I8 then engages the front surface of this same tooth thereby locking the ratchet wheel in this position. When the armature is released the pawl moves forward and projection 25 engages the next tooth of the wheel. The detent I8 is pivoted at I9 and has a long extension so that the force of gravity will immediately cause the detent to engage the next tooth as soon as the armature has operated.

Each of the cam wheels have two projections or cams directly opposite each other on the circumference of the wheel. Each wheel is mounted so that its cams will be displaced 36 or one-tenth of a revolution with respect to the adjacent wheels. Thus as the switch is stepped the spring combinations will be operated in order one after the other.

' In the position illustrated in Fig. 2, the spring combination shown is operated by cam wheel 36 and has just been returned to normal at the last step of the switch after having been operated at the previous step of the switch by the projection 38 of Wheel 36. The spring combination (not shown) controlled by cam wheel 35 would be operated in the position shown in this gure. Armature spring 40 of the spring combination shown is operated directly by the cam and operates the armature springs 43 and 44 by means of the bushings 4I and 42.

The improved switch is especially adapted foruse in radio program service system and this embodiment of the invention has been illustrated in the circuit diagram Fig. 4. In a system of this type, a plurality of radio receiving sets are provided at the distributing station, each tunedto' receive the program of a different broadcasting station. A program selector such as has been described is provided for each subscriber entitled to the program service. Five of these switches l may be mounted on a Strowger connector base such as is well known in the art of automatic telephony. A two conductor line extends from a subscribers program selector to a loud speaker (not shown) at the subscribers premises. A push button is provided at the subscribers premises for controlling his program selector.

The leads extending fromY each receiving set are multipled into corresponding spring combinations of all program selectors. The number of programs available to the subscribers is limited by the number of cams and spring combinations provided on the selectors. An ammeter is provided for each program and is multipled to each selector. The readings of these ammeters are an indication of the popularity of the various programs.

When a subscriber wishes to tune in on a program he turns on a switch (not shown) which connects his speaker to the line and he immedately receives one of the programs depending upon the position of his selector. It will be assumed that the selector is in the-position shown and the subscriber is receiving program #1. It will be further assumed that he wishes to listen to program #2. Accordingly, he depresses the push button 62 and again releases it thereby momentarily closing a circuit from battery, upper winding of stepping magnet 2, conductor 60, push button 62 and its make contact, conductor 6|, lower winding ofstepping magnet 2, to ground. Magnet 2 momentarily energizes and advances the selector one step thereby revolving the cams through one-tenth of a revolution. This causes the projection of cam 35 to operate armature spring 18 which in turn operates springs 'I9 and 80. At the same time the spring combination controlled by cam 36 is returned to normal.

The operation of the spring combination controlled by cam 35 completes the circuit from the receiving set lead 10, spring 18 and its make contact, conductor 66, condenser 65, conductor 6l of the subscribers line, condenser 63, loud speaker at subscribers premises, conductor 60, condenser V64, conductor 61, 4make lspring controlled by armature 19 and said armature, lead 'Il to the receiving set. Program #2 is now received at the lsubscribers loud speaker.

In order to compensate for the' continual variation in the number of subscribers Alistening to each program, a compensating resistance such as 12 or 11 is provided at each selector for each program. 'Ihis resistance is rthe equivalent of the subscribers'loud speaker and is connected across the back contacts of the armature springs such as 40 and 43 or 18 and 19. Thus in the assumed case, when the subscriber stepped his selector to program #2 and the spring combination controlled by cam 36 returned to normal, resistance 12 was substituted for the subscribers loud speaker across the leads from the receiving set. In this way the volume of reception of other subscribers listening to this program is not affected.

. In order that the attendant at the distributing station may determine which programs are the most popular with the subscribers, an ammeter is provided for each program. These ammeters are multipled to all the selectors. Thus in the assumed. case, when the subscriber stepped his selector to program #2, a circuit was closed from ground, resistance 15, armature 8i) and its make contact, conductor 16ammeter 8|, to battery. The current flowing in this circuit caused the reading of the ammeter 8| to increase. On thel other hand, when the spring combination controlled by cam 36 returned to normal, the opening of armature spring 44 and its make contact caused the reading of ammeter 82 to decrease. Thus the reading of the ammeters is an indica.- tion to the attendant of the relative number of subscribers using each program and in this way the most popular programs can be selected and made available to subscribers of the service.

As an additional feature of the service and also as a means for informing a subscriber of the position of his selector, the leads 68 and 69 may be extended to a time signalling device in'- stead of to a receiving set. If this arrangement is employed, a subscriber may step his switch until he hears the time signals. He then knows that his selector is in position I and if he wishes to tune in on the program connected to position #4 he knows that he must-advance his selector three steps.

The spring I2 and contact I3 previously explained as being operated by the armature of the stepping magnet are used to bring in an alarm in case the stepping magnet of any selector is held energized by a short circuit of a subscribers line or a grounded line. Spring I2 is connected to battery and contact I3 `is connected to a slow acting alarm `equipment (not shown). If the stepping magnet remains energized due to some fault von the line, a circuit is closed to the slow acting alarm equipment and after a predetermined interval an alarm is sounded calling the attendants attentionV to this condition.

Although a, particular embodiment of the improved selector switch has been disclosed, the invention is not limited to this particular application but may be applied to many other uses by those skilled in the art without departing from the spirit of the invention.

Having described the invention, what is thought to be new and is desired to have protected by Letters Patent will be set forth in the appended claims.

What is claimed is:

1. In a program service system, a program selecting switch comprising a magnet, a shaft having a plurality of cams, and a contact set for each of said cams, a plurality of program circuits each connected to operating springs of a different one of said contact sets, a two-conductor line extending from a subscribers static-n and terminating in windings on said magnet, a branch of said line connected in multiple to working contacts of the operating springs in each of said contact sets, a key at said subscribers station for controlling said magnet to rotate said shaft and cams thereby connecting said line to each of said program circuits in turn,` and a resistance connected to resting contacts of the operating springs in each contact set so that each resistance is bridged across its ass-ociated program circuit when the contact set is at normal.

2. In a program service system, a plurality of program selecting switches each terminating a line incoming from a subscribers station, a plurality of contact sets in each switch, multiple connections between each subscribers line and the contact sets in the associated switch, a like plurality of program circuits each connected in multiple to corresponding contact sets in each switch, a plurality of cams in each switch, one for each contact set, means controlled from a subscribers station for rotating the cams of the associated switch to successively operate the contact sets thereby connecting the subscribers line to each of said program circuits in turn, an ammeter for each program circuit, and multiple circuits for each ammeter extending through the corresponding contact set of each switch.

3. In a system for distributing sound-carrying or image-carrying currents from a number of sources from a central station to a number of distantly located stations, conductors between said central station and said distantly located stations, a selective device for each distant station located at a point convenient to the central station, each of said devices having a series of double throw switch units, each connectable with one of said sources of current, a reproducer for each of the distant stations connected with one of said selective devices, means controllable at each distant station for operating one of said selective devices to select a connection with any one of said sources, and an impedance normally connected with each of said double throw switch units and similar in value to the combined impedance of the subscribers line and reproducer which is served by the selective device of which said switch unit comprises a part.

4. In a system for distributing currents from a number of different sources of sound carrying or image carrying currents, from a central station to Va number of distantly located stations, a reproducer at each distantly located station, conductors between said central station and said distantly located stations, a selective device for each distant station located at a point convenient to the central station, each of these devices having a unidirectionally progressive movable actuating element and a series of double throw switch units, the movable contacts of each of said double throw switch units connected to one of said sources, one of the two sets of stationary contacts of each of said double throw switch units connected through the subscribers line to ther subscribers reproducer, and the other set of stationary contacts of each of said double throw switch units connected to an impedance unit having an impedance approximately equal to the impedance of the subscribers line and reproducer, and means controllable at each distant station for operating one of said selective devices to select a connection with any one of said sources.

5. In a system for distributing sound carrying or image carrying currents from a number of different sources, from a central station to a number of distantly located stations, a reproducer at each distantly located station, conductors between said central station and said distantly located stations, a selective device for each distant station located at a point convenient to the central station, each of said devices having a series of double throw switch units, the movable contacts of each of said double throw switch units connected to one of said sources, one of the two sets of stationary contacts of each of said double throw switch units connected through the subscribers line to the subscribers reproducer, and the other set of stationary contacts of each of said double throw switch units connected to an impedance unit having an impedance approximately equal to the impedance of the subscribers line and reproducer, and means controllable at each distant station for operating one of said selective devices to select a connection with any one of said sources.

6. In a selective switch, a rectangular Trame, a shaft extending transversely across said frame at one end thereof and having bearings in the sides thereof, the said shaft being long enough so as to extendbeyond the frame on -both sides, a plurality of cams mounted on said shaft outside the frame, part on one side thereof and part on the other, a bracket attached to each side of said frame, sets o-f contact springs mounted on said brackets, one set for each cam, a stepping magnet within said frame and secured to the end thereof opposite said shaft, ratchet mechanism for rotating said shaft, and an armature pivoted inside said frame, whereby said magnet operates said ratchet mechanism.

7. In a system for distributing sound carrying or image carrying currents from a central station to a distant station. a number of different sources of sound or image carrying currents available at the central station, a selective switching device of the uni-directional, step by step, magnetically actuated type located at a point convenient to the central station and having a series of switch units each connected with one of said current sources, a reproducer at the distant station, a pair of conductors only, connecting said switching device with said reproducer and adapted to transmit said sound or image carrying currents, an electrical circuit for controlling said switching device extending between said device and said distant station and comprising essentially; a pair of conductors, at least one of which constitutes one of said first mentioned pair of conductors, a source of electrical energy available at said switching device, a stepping magnet connected in series with said source of electrical energy and with said last mentioned pair of conductors, and means at said distant station for making and breaking a connection between said last mentioned conductors to progressively actuate said switching device.

8. In a system for distributing sound carrying or image carrying currents from a central station to a distant station, a number of different` sources of sound or Image carrying currents available at the central station, a selective switching device of the uni-directional, step by step, magnetically actuated type located at a point convenient to the central station and having a series of switch units, each connected with one of said current sources, a reproducer at the distant station, a pair of conductors only, connecting said switching device with said reproducer and adapted to transmit said sound or image carrying currents, an electrical circuit for controlling said switching device extending between said device and said distant station and comprising essentially; a pair of conductors, at least one of which constitutes one of said first mentioned pair of conductors, a source of electrical energy available at said switching device, a stepping magnet connected in series with said source of electrical energy and with said last mentioned pair of conductors, and a normally open switch at said distant station for making a connection between the conductors of said last mentioned pair, to progressively actuate said switching device.

THEODORE C. RIEBE. CLARENCE E. LOMAX. HERBERT F. OBERGFELL. 

